Stabilized creamed food products



Patented Sept. 29, 1953 UNITED STATES PATENT OFFICE Calif., assignors tothe United States of America as represented by the Secretary ofAgriculture No Drawing. Application August 12, 1952, Serial No. 304,053

(Granted under Title 35, U. S. Code (1952),

sec. 266) 7 Claims.

A non-exclusive, irrevocable, royalty-free license in the inventionherein described, for all governmental purposes, throughout the world,with the power to grant sublicenses for such purposes is granted to theGovernment of the United States of America.

This application is a continuation-in-part of our copending applicationSer. No. 191,914, filed Oct. 24, 1950, now abandoned.

This invention relates to the preparation of edible compositions ofmatter of the type which are commonly thickened by the use of starches,flours, or other amylaceous materials, such compositions being, forexample, sauces, gravies, creamed meat dishes, cream soups, puddings,custards, pie fillings, salad dressings, and so forth. In particular,this invention concerns the use of waxy rice flour or waxy rice starchin such compositions as the thickening agent whereby the resultingcomposition is stabilized in that it will retain its smooth, creamytexture and will exhibit little if any separation of liquid. Thecompositions in accordance with this invention containing waxy riceexhibit this stability even after being subjected to preservationprocedures and storage prior. to ultimate use. Thus the compositionsretain their smooth, creamy texture and exhibit little if any separationof liquid even after being frozen and thawed or even after being subected to canning and storage for extended periods of time. Consequentlyour products are not subject to quality deterioration by the effect offreezing and thawing or by the eifect of canning and storage as are theproducts heretofore known.

Although our invention is especially adapted to the preparation ofsauces and gravies, it is also applicable to all types of food productswhich consist entirely or in part of a thickened liquid mass, suchproducts including creamed meat dishes, creamed vegetable dishes,creamed meat and vegetable dishes, puddings, custards, salad dressings,pie fillings, creamed soups, and so forth.

The problems with which this invention is concerned may be explained asfollows, particular reference being made to pre-cooked, frozen creamedchicken merely by way of example.

The preparation of pre-cooked, frozen creamed chicken usually involvesthe following technique: The chicken is first cooked in water and themeat then separated from the bones and minced into suitable smallpieces. A white sauce containing fat, milk, wheat flour or corn starch,and salt is then prepared and mixed with the minced meat.

This composition is then packaged, frozen, and maintained in frozenstorage until ready to be used. When such a product is thawed for use,two undesirable changes will be noted. In the first place the thawedmaterial will show phase separation, that is, the emulsion will bebroken and a watery liquid will exude out of the mass. In the secondplace, the mass will no longer be smooth and creamy but exhibits a lumpytexture, in extreme cases resembling the appearance of curdled milk orcottage cheese. These changes are of course adverse to the wideutilization of pre-cooked frozen foods of this type primarily becausethe non-technical consumer is led to believe that the product is spoiledor of low quality. These deleterious changes are due to the type ofstarchy material used, as hereinafter explained, and will occur with allof the starchy materials generally used for such purposes, for examplewheat flour or starch, corn starch, rice flour or starch and so on. As amatter of fact the undesirable changes which occur on thawing are notentirely irreversible as the composition may be stirred vigorously whileheating thus to form a product which approximates the original creamyemulsion. However, in practice such vigorous stirring cannot be usedbecause it would tend to mash the solid components of the product suchas the minced meat, or vegetables if such are present. This problem ofthe deleterious changes in creamed products upon thawing has been knownin the industry for many years but heretofore no one has succeeded inalleviating the situation.

The problems outlined above in connection with frozen, creamed chickenare also involved in preparing canned creamed products. Thus for examplewhen a creamed soup is made in the customary manner by thickening soupingredients with corn starch or wheat flour and the product canned, thatis, placed into hermetically sealed containers and subjected to heat tosterilize the product so that it will keep indefinitely, it will beobserved that the product does not r tain its creamy texture. As thecanned product is stored, its viscosity increases and it becomes more ofa gel rather than merely a thickened liquid. With further storage, theproduct becomes a rubbery gel which eventually shrinks, exuding wateryliquid about the gell matrix. In some cases, the product may also becomelumpy and exhibit a curdled appearance. In any'case all of thesechangesincrease in viscosity, gelling, exudation of watery liquid, andcurdlingare deleterious in that when the can is opened 3 by the consumerthe product does not present an attractive appearance and is diflicultto remove from the can. Reconstitution of the product to re-form itscreamy texture requires application of heat and vigorous stirring, thelatter being undesirable as it tends to mash solid components of theproduct such as minced meat, vegetables, etc. As set forth above inconnection with the frozen products, the deleterious changes which occuron storage after canning are due to the starchy material used as thethickening agents.

We have now found that the problems briefly explained above can beremedied in a very simple and expeditious manner. In essence, our newdeparture primarily involves using waxy or glutinous rice (Oryzaglutinosa) as the thickening agent in preparation of the sauce, gravy orother creamed product. Thus the food product is prepared in the usualand customary manner except that waxy rice flour is used instead of thewheat flour or starch or other commonly used thickening ingredient. Inmany cases, the waxy rice flour need not be used as the sole thickeningagent but can be used to replace part of the ordinary thickening agent.The food products prepared in accordance with this invention, whenfrozen and thawed or when canned and stored, do not undergo anydeleterious changes. The sauce remains smooth and creamy and the productshows very little, if any, exudation of liquid. Thus by the applicationof this invention it is possible for the first time to prepare apre-cooked, creamed frozen product which when thawed presents anappetizing appearance like the freshly prepared product. It is alsopossible for the first time to prepare a canned creamed product whicheven after storage presents an appetizing appearance like the freshlyprepared product. Further, the products produced in accordance with thisinvention have the desirable property of being short pastes and do nothave the gummy or "long character of pastes obtained with tapioca orwaxy maize starch.

It is to be emphasized that in proceeding in accordance with thisinvention we use a particular type of starchy material, 1. e., thatderived from waxy rice. This material is to be contrasted with normalrice flour or starch. The differences between the normal and waxystarches can be explained as follows. The starch from the normal cerealssuch as corn, wheat, rice, potato, tapioca, etc. contains to 30% ofamylose and 70- 85% amylopectin. These fractions, amylose andamylopectin, have entirely distinct structure and properties. Thusamylose is of linear structure and is soluble in hot water, the solutionshowing an exaggerated tendency to retrograde or revert to the insolublestate on cooling. It is the amylose fraction of the normal starcheswhich makes them useful for production of gels by virtue of thisretrogradation property. Further, amylose yields a blue coloration uponcontact with iodine. On the other hand, amylopectin has a branchedstructure and is soluble in water at concentrations of 5-10%, suchsolutions being relatively stable in a physical sense. Further,amylopectin yields a red or violet coloration upon contact with iodine.In contrast to the normal cereals, there are waxy or glutinous strainsof some cereals. namely, maize, sorghum, rice, rye, and barley. No waxystrains of wheat or the root or tuber starches have been found. Thestarches from these waxy or glutinous cereals are virtually pureamylopec- 4 tin. The composition of some typical starches is set forthin the following table:

Composition of starches from various sources 1* Amylose, Amylopcctin,arch percent percent Maize 0 It is to be emphasized that difference inproportions of amylose and amylopectin is not the sole basis for thedifferences between various starches. The point is that the amylose andamylopectin fractions of each starch differ from one another in suchattributes as length of molecular chains, degree of branching, molecularweight, and so forth. Thus for example, wheat starch and tapioca starchhave virtually the same amylose-amylopectin proportion yet each of thesestarches will produce a different type of paste. Wheat starch paste haswhat is known in the industry as a short texture whereas tapiocaproduces a paste of glutinous or long" texture.

We have found that the starch of waxy rice is outstanding among starchesfor the purposes of this invention. In the first place, the paste orcreamed product produced with the waxy rice is stable to freezing andthawing and stable when canned. and stored. In this respect it is farsuperior to normal starches and even superior to waxy maize starch whichbecause of its high amylopectin content would be expected to yiel apaste stable to freezing and thawing and canning and storage. Anotherimportant point is that waxy rice flour yields a short" paste which isessential in the production of sauces and gravies and usually preferredin the case of puddings and similar desserts. Thus the paste with waxyrice flour is similar to that prepared with wheat flour or normal cornstarch. In contrast, waxy maize starch yields a glutinous or long pastewhich because of its cohesive and gummy nature is totally unsuited forthe preparation of sauces and gravies. The waxy maize paste is quitesimilar to that produced with tapioca and as a matter of fact waxy maizestarch came into wide use during the recent war as a substitute fortapioca when supplies of the latter were cut off by the exigencies ofwarfare.

The application of the principles of this invention to the preparationof any desired type of foodstuff presents no problems. It is merelynecessary to substitute the waxy rice for the conventional flour orstarch in the cooking recipe. In some cases the waxy rice will have tobe used in somewhat greater proportion than the starch or flour it isreplacing in order to get the same viscosity. The proper amount of waxyrice to use in any particular instance can easily be determined by theuse of a standard calibrated flow table or other device suitable formeasuring the viscosity of a sauce or gravy. Another point to be notedis that the stabilizing power of waxy rice is so great that it need notbe used as the sole thickening agent but may be mixed with the normal(high amylose) starch in the proportion of,

say, 20 to 80% waxy rice, the remainder being the normal starch orflour. As in the preparation of known creamed food products, theessential step in preparing our novel products is to disperse the waxyrice in the water or other aqueous edible medium, as for example, milk,broth, fruit juice, and so forth. Such dispersing entails stirring thewaxy rice into the liquid and cooking for a short period to ensurecomplete dispersion. The concentration of waxy rice depends on thethickness of the product desired, usually a concentration from about 2%to about is desirable. The resulting thickened liquid is then admixedwith the desired flavoring agents or other food items such as meat,eggs, vegetables, or fruit and sugar, depending on the type of productdesired. Colloidal materials such as gelatin, gum tragacanth, Irish mossextra-ct, etc. may be added to obtain thicker or more gel-like products.Where the food product is to contain a fat it is usually advantageous tofirst blend the fat and the waxy rice and then add the liquid and cookthe mixture with stirring for a few minutes. After addition of thedesired flavoring ingredients or additional nutrient matter the mass ispackaged in suitable containers such as cartons or cans, frozen, andmaintained in frozen storage. If it is desired to prepare a cannedproduct then the mass is placed into containers, such as cans or glassjars, which are sealed then subjected to heat, the temperature and timeof heating being regulated to assure sterilization of the product sothat it will keep indefinitely. The most economical way of employing thewaxy rice is as the flour which is made by grinding the separatedendosperm of the waxy rice. If desired one can use the waxy rice starchprepared by subjecting the flour to a separation treatment to remove itsprotein content.

In applying this invention to the preparation of pre-cooked, frozen,creamed turkey or chicken, we find it advantageous to initially cook thefowl in the presence of an antioxidant thus to retard oxidation of theturkey or chicken fat during the cooking process. Details regarding theuse of this technique are described and claimed in the patentapplication of H. Lineweaver, H. L. Hanson, and A. A. Klose, entitledStabilized Meat Products, Serial No. 188,861, filed October 6, 1950.

The following examples demonstate our invention in greater detail. It isunderstood that these examples are furnished only by way of illustrationand not limitation.

EXAMPLE I A series of white sauces were prepared and tested as follows:

In each case the white sauce was prepared by first melting theshortening and blending it with the flour or starch. The milk wasseparately heated to 60 C. then added to the shorteningthickening agentand blended all at Once with stirring. This mixture was boiled for oneminute and the salt added during the last seconds of the boil. Theproducts were then packaged in cans, frozen, and maintained in frozenstorage at 0 F. for two months. After this period of time the sampleswere tested for quality in the following manner:

Two cans of each lot were subjected to thawing while the product wasstill in the can. The contents were then removed and subjected tocentrifugation and filtration to separate the watery liquid, if any,from the sauce, the amount of liquid exudate being measured.

Two cans of each lot were subjected to thawing while the product wasstill in the can. The contents of each can were then poured into a petridish and the appearance of the various samples determined by a panel ofpersons skilled in the art of judging quality of foods. For controls,samples of white sauce were prepared just prior to the qualitydetermination. These control samples were of course not subjected to anyfreezing treatment.

The recipes of the various samples of white sauce are listed below.Samples A and B were prepared in accordance with this invention, theother samples being prepared with various flours and starches nowcommonly used in the preparation of creamed foodstufis, these samplesbeing included for the sake of comparison with applicants products.

- Grams A. Waxy rice flour 35 I Hydrogenated vegetable shortening--- 25Milk 488 Salt 3 B. Waxy rice flour 17.5 Wheat flour 12.5 Shortening,milk, and salt as in A 0. Wheat flour 25 Shortening, milk, and salt asin A D. Waxy maize starch 23 Shortening, milk, and salt as in A It is tobe noted that the amount of thickening agent is different in eachsample. This was done in order to produce truly comparative sauces. Thususing the proportions stated, each sauce had the sameviscosity, i. e., aline spread of approximately 24 as measured on a standard calibratedflow table.

The results of the tests are set forth in the following tables:

TABLE 1 Liquid separation from products after thawing Amount of liquidwhich Sample Thickening agent used separated on thawing, percent 1 AWaxy rice flour 0 Waxy rice flour and wheat flour. 6 Wheat flour 41 Waxymaize starch 23 1 The figures in this table are averages of duplicatelots of each sample of white sauce.

TABLE 2 Appearance of products on thawing Score for Sample Thickeningagent used appearance 1 A waxyricefiour 9.3 B waxy rice flour and wheat1101 1.... 6.0 C wheatflour 4. D waxy maize starch 2. 2 Control 1 waxyrice flour.. 10.0 Control 2 3 wheat flour 8. 6

lhe figures in this table are averages of duplicate lots of each sampleof white sauce. The products were judged on a basis of 10 for smooth andcreamy texture and l for very watery or curdled.

1 Control 1 was a freshly-prepared sample of white sauce prepared inaccordance with recipe A and not subjected to freezing.

1 Control 2 was a freshly-prepared sample of white sauce prepared inaccordance with recipe 0 and not subjected to freezing.

EXAMPLE II A series of chicken gravies were prepared and tested asfollows:

- In each case the gravy was prepared by first melting the chicken fatand blending it with the flour or starch. The broth, drippings, andvwater were then stirred into the blend and the mixture boiled withstirring for a few minutes to get a smooth gravy. The salt was addedduring the last period of the boiling operation. The products werepackaged in cans, frozen and allowed to stand at F. for one month. Afterthis period of time, the products were tested for liquid separation andappearance by the methods set forth in Example I. The recipes for thevarious samples of gravy are listed below. Sample A was prepared inaccordance with this invention, the other samples being prepared withcommonly used thickening agents, these samples being included for thesake of comparison with applicants products:

Grams A. Waxy rice flour '70 Chicken fat 50 Chicken broth and drippings405 Water 571 Salt 6 B. Waxy maize starch I 44 Chicken fat 50 Chickenbroth and drippings 405 Water 771 Salt 6 (More water was required inthis case to make the gravy of the same thickness as gravies A and C.)

C. Wheat flour 50 Chicken fat 50 Chicken broth and drippings 405 Water571 Salt 6 The results of the tests are shown in the following tables:

TABLE 3 Liquid separation cfpzcducts aficr thawing Amount of liquidwhich Sample Thickening agent separated on thawing, percent waxy riceflour O waxy maize starch. 33. 8 wheat flour 57. 5

TABLE 4 Appearance of products on thawing Sample Thickening Agent igggfag 1 A waxy rice flour 9. 7 waxy maize starch. 4. 5 wheat flour 2. 2

l Thev products were scored on dbasisof 10 for smooth and. creamytexture andl for very watery 0r curdled.

EXAMPLE III waxy rice flour, 3.9.

cornstarch, 2.9.

Amylaceous material,

milk, sugar, percent. salt, percent water, percent vanilla, percent Inpreparing product B, the proportions of amylaceous material and gelatinwere somewhat above the proportions of these ingredients in product A sothat both A and B would have the same initial consistency. In each case,the amylaceous material, sugar, and salt were stirred until smooth withpart of the milk (cold). The remaining milk was scalded, the abovemixture was added, and the material was cooked 15 minutes while stirringconstantly until it thickened. The gelatin moistened with the water wasthen stirred in and finally the vanilla wa incorporated with stirring.The pudding mix was then cooled, packaged, and frozen at 0 F. Afterstoring at 0 F. for 1 day and for 9 months, respectively, samples of thefrozen pudding were allowed to thaw and examined. The results obtainedare tabulated below:

Texture after thawing Product Stored 1 day at 0 F. Stored 9 Inc. at 0 F.

Custard-type desserts were prepared employing the following ingredients:

cornstarch, 3.0...

amylaceous material, waxy rice flour, 3.0.

percent.

egg yokcs, pcrcent'....

milk, perccnt.

sugar, percent salt, pcrcent..

vanilla, percen In each case, a small amount of the milk (cold) wasmixed with the egg yolks and a small amount of the milk (cold) was mixedwith the dry ingredients. The remaining milk was heated to 70 C. and toit was added the mixture of cold milk, amylaceous material, sugar, andsalt; the material was heated in a double boiler (-95 C.) with constantstirring for 10 minutes. This hot mixture was then added with stirringto the yolk-milk mixture and the material heated in a double boiler(85-90" C.) with stirring for 10 minutes. The vanilla was then added andthe custard mix was packaged, cooled, and frozen at 0 F. After storingat 0 F. for 1 day and for 2 months, respectively, samples of the frozencustard were allowed to thaw and examined. The results obtained aretabulated below:

A series of products were prepared employing the following ingredients:

Percent Amylaceous material (as specified below) 5 Salt 1 Water 94 Ineach case the amylaceous material (wheat flour, waxy rice flour, cornstarch, and waxy maize starch, respectively) and salt were stirred withcold water to get a uniform dispersion and the dispersion then heatedwith constant stirring until it thickened. The thick material, of theconsistency of a sauce or gravy, was filled into cans which were thensealed and autoclaved at 240 F. for 60 minutes to ensure sterilization.Samples of the products as immediately prepared and after storage in thecans for 30 days at 25 C. were subjected to viscosity tests andmeasurements of their modulus of elasticity. Also after storage at 25 C.in the cans, the products were examined as to texture. The results aresum- 10 substantially no watery liquid and will retain a smooth andcreamy texture when frozen and thawed.

4. A frozen cooked food product which in the unfrozen state is ofsauce-like to custard-like consistency comprising a frozen edible liquidthickened with waxy-rice, said product being characterized in that itwill exude substantially no watery liquid and will retain a smooth andcreamy texture when thawed.

5. A frozen cooked food product which in the unfrozen state is ofsauce-like to custard-like consistency comprising a frozen aqueousemulsion of fat thickened with waxy rice, said product bemarized below:ing characterized in that it will exude substan- Expt. 1 Expt. 2 Expt. 3Expt. 4 Amylaceous material wheat flour waxy rice flour cornstarch..Waxy maize starch. Initial viscosity, poises at C. 2.3 6.9 2.1 1.6.Viscosity after storage, days at 5 0.7.

25 0., poises at 25 0. Initial modulus of elasticity, 0.051 0.046 0.002.

g./sq. cm. Modulus of elasticity after storage 0.114 0.14

for 30 days at 25 0.. g./sq. cm.

Appearance after storage for 30 Too stifl to pour Smooth, no liquid daysat 25 C. from can, showed separation, could from can, showed 0 a n t hin a n d liquid separabe poured from liquid separawatery. tion. can.tlon.

Too stifl to pour Entire contents of 1 Too low to be measurable.

It is evident from the above data, that the product made with waxy rice(Expt. 2) retained its viscosity and modulus of elasticity (a measure ofthe amount of gelation) constant for 30 days storage after canning. Onthe other hand the products made with wheat flour and corn starch(Expts. 1 and 3) increased in viscosity and degree of gelation. Theproduct made with waxy maize starch (Expt. 4) became thin and waterythus entirely losing its original sauce-like nature.

In this series of experiments, no flavoring other than salt was used toavoid any extraneous effects on the experiments. It is obvious that inpractice of the invention, it would be preferable to add to theingredients of Expt. 2, various flavorings or nutriments such as meatbroth, fat, minced meat or vegetables, for preparing sauces, gravies, orsoups or to add sugar and other suitable fiavorings for making dessertproducts.

Having thus described our invention, we claim:

1. A cooked food product of sauce-like to custard-like consistencycomprising an edible liquid thickened with an amylaceous material atleast 20% of which is waxy rice, said product being characterized inthat it will exude substantially no watery liquid and will retain asmooth 1 and creamy texture when frozen and thawed.

2. A cooked food product of sauce-like to custard-like consistencycomprising an edible liquid thickened with waxy rice, said product beingcharacterized in that it will exude substantially no Watery liquid andwill retain a smooth and creamy texture when frozen and thawed.

3. A cooked food product of sauce-like to custard-like consistencycomprising an aqueous emulsion of fat thickened with waxy rice, saidproduct being characterized in that it will exude tially no wateryliquid and will retain a smooth and creamy texture when thawed.

6. A cooked food product of sauce-like to custard-like consistencycomprising an edible liquid thickened with an amylaceous material atleast 20% of which is waxy rice, said product being characterized inthat it will exude substan tially no watery liquid and will retain asmooth and creamy-texture when frozen and thawed, said product alsobeing characterized in that it will exude substantially no watery liquidand will retain a smooth and creamy texture when subjected to canningand storage in the canned state.

7. A canned, cooked food product of sauce-like to custard-likeconsistency comprising an edible liquid thickened with waxy rice, saidproduct being characterized in that it will exude substally no wateryliquid and will retain a smooth and creamy texture when subjected tostorage in the canned state.

HELEN L. HANSON. HANS LINEWEAVER.

References Cited in the file of this patent Waxy Cornstarch As aReplacement for Tapioca, by Schopmeyer et al. Industrial and EngineeringChemistry, November 1943, vol. 35, No. 11, pages 1168-4172.

Amioca, The Food Packer, August 1944, pages 32, 33 and 72.

Glutinous Corn and Sorghum starches, by MacMasters et al. Industrial andEngineering Chemistry, vol. 36, No. 10, October 1944, pages 958-963.

The Freezing Preservation of Foods, Tressler and Evers, Avi PublishingCo., New York, 1947, Second Edition, pages 658-660.

1. A COOKED FOOD PRODUCT OF SAUCE-LIKE TO CUSTARD-LIKE CONSISTENCYCOMPRISING AND EDIBLE LIQUID THICKENED WITH AN AMYLACEOUS MATERIAL ATLEAST 20% OF WHICH IS WAXY RICE, SAID PRODUCT BEING CHARACTERIZED INTHAT IT WILL EXUDE SUBSTANTIALLY NO WATERY LIQUID AND WILL RETAIN ASMOOTH AND CREAMY TEXTURE WHEN FROZEN AND THAWED.